I think I remember someone posting somthing in a similar thread a while back showing that the DD 7.0 was actually lighter than standard CAR length handguards. A photo of the two on scales or somthing like that.

Rifle has sights and sling swivels to accept a standard sling. Without drilling holes in parts or shaving the front sight (or part of the carry handle) you really can't make a lighter 'standard' AR-15. This is lighter than a Bushmaster Carbon 15 flattop and lighter than the Carbon 15 Model 4

The only 'AR type' that is lighter is the Bushmaster Carbone 15 Type 97S which doesn't have an ejection port cover, nor does is have sling swivels to accept a standard sling (It also can't accept other stocks).